The effect of retinyl-palmitate on the level of pro and anti-inflammatory cytokines in multiple sclerosis patients: A randomized double blind clinical trial.

OBJECTIVE Multiple sclerosis (MS) is an inflammatory and autoimmune disease associated with the imbalance of cytokines secreted from CD4+ T cells. Studies have shown that vitamin A and its active derivatives are able to modulate the immune system in MS patients. The aim of the present study was to investigate the effect of supplementation of retinyl palmitate (RP), the dietary form of vitamin A, on pro- and anti-inflammatory cytokines in the plasma and supernatants of cultured peripheral blood mononuclear cells (PBMCs) of MS patients. PATIENTS AND METHODS Thirty-six relapsing-remitting MS patients were enrolled in this double-blind randomized clinical trial. Participants received one capsule of 25,000 IU RP or a placebo per day for six months. Blood samples were taken before and after intervention. After intervention, the PBMCs were isolated and cultured. The levels of pro- and anti-inflammatory cytokines in the plasma and supernatant of cells stimulated with myelin oligodendrocyte glycoprotein, phytohemagglutinin or vehicle (media) were determined. The sample t-test and Mann Whitney U test were used to compare data between groups. RESULTS The changes in pro-inflammatory cytokine levels (IL-1β, TNF-α, IFN- γ, IL-2, IL-6, and IL-17) in the serum and supernatant of MS patients were not significant (p > 0.05). There were also no significant changes in the levels of anti-inflammatory cytokines (IL-10, IL-13, IL-4, and TGF-β) (p > 0.05). CONCLUSION Unexpectedly, this study found no significant changes in cytokine levels after six months of RP supplementation in MS patients. The results of other studies by our team have shown significant changes in the gene expression of the cytokines in response to RP supplements. Therefore, we recommend that periodic follow-up of RP supplementation may be needed to reveal changes in the level of the cytokines in the plasma and PBMCs and to clarify the real effect of RP on the immune factor levels in the serum of MS patients.